diff options
author | Jeff Dike <jdike@addtoit.com> | 2007-10-16 10:27:26 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 18:43:08 +0200 |
commit | b160fb6309dc907cbd8849e549d83badb86dd35b (patch) | |
tree | b4a69cc1b96b4aa83aa971c35af5a23e5e07b56f /arch/um/os-Linux/time.c | |
parent | uml: tickless support (diff) | |
download | linux-b160fb6309dc907cbd8849e549d83badb86dd35b.tar.xz linux-b160fb6309dc907cbd8849e549d83badb86dd35b.zip |
uml: eliminate interrupts in the idle loop
Now, the idle loop now longer needs SIGALRM firing - it can just sleep for the
requisite amount of time and fake a timer interrupt when it finishes.
Any use of ITIMER_REAL now goes away. disable_timer only turns off
ITIMER_VIRTUAL. switch_timers is no longer needed, so it, and all calls, goes
away.
disable_timer now returns the amount of time remaining on the timer.
default_idle uses this to tell idle_sleep how long to sleep. idle_sleep will
call alarm_handler if nanosleep returns 0, which is the case if it didn't
return early due to an interrupt. Otherwise, it just returns.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r-- | arch/um/os-Linux/time.c | 54 |
1 files changed, 11 insertions, 43 deletions
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c index 9ffc61ac8ed6..d2cb161ae2b3 100644 --- a/arch/um/os-Linux/time.c +++ b/arch/um/os-Linux/time.c @@ -12,8 +12,6 @@ #include "os.h" #include "user.h" -static int is_real_timer = 0; - int set_interval(void) { int usec = 1000000/UM_HZ; @@ -41,47 +39,15 @@ int timer_one_shot(int ticks) return 0; } -void disable_timer(void) +unsigned long long disable_timer(void) { - struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }}); + struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } }); - if ((setitimer(ITIMER_VIRTUAL, &disable, NULL) < 0) || - (setitimer(ITIMER_REAL, &disable, NULL) < 0)) + if(setitimer(ITIMER_VIRTUAL, &time, &time) < 0) printk(UM_KERN_ERR "disable_timer - setitimer failed, " "errno = %d\n", errno); -} - -int switch_timers(int to_real) -{ - struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }}); - struct itimerval enable; - int old, new, old_type = is_real_timer; - - if(to_real == old_type) - return to_real; - - if (to_real) { - old = ITIMER_VIRTUAL; - new = ITIMER_REAL; - } - else { - old = ITIMER_REAL; - new = ITIMER_VIRTUAL; - } - - if (setitimer(old, &disable, &enable) < 0) - printk(UM_KERN_ERR "switch_timers - setitimer disable failed, " - "errno = %d\n", errno); - if((enable.it_value.tv_sec == 0) && (enable.it_value.tv_usec == 0)) - enable.it_value = enable.it_interval; - - if (setitimer(new, &enable, NULL)) - printk(UM_KERN_ERR "switch_timers - setitimer enable failed, " - "errno = %d\n", errno); - - is_real_timer = to_real; - return old_type; + return tv_to_nsec(&time.it_value); } unsigned long long os_nsecs(void) @@ -92,11 +58,13 @@ unsigned long long os_nsecs(void) return timeval_to_ns(&tv); } -void idle_sleep(int secs) +extern void alarm_handler(int sig, struct sigcontext *sc); + +void idle_sleep(unsigned long long nsecs) { - struct timespec ts; + struct timespec ts = { .tv_sec = nsecs / BILLION, + .tv_nsec = nsecs % BILLION }; - ts.tv_sec = secs; - ts.tv_nsec = 0; - nanosleep(&ts, NULL); + if (nanosleep(&ts, &ts) == 0) + alarm_handler(SIGVTALRM, NULL); } |